1. St. Bonaventure College and High School Form 4 Biology Bridging Course 2009-2010 Cell structure

2. The structures of animal cells and plant cells Cell is the basic unit of life. There are more than 200 types of cells in our body. The shape and size of cells vary, but some features are common to all.

3. Electron microscope The first electron microscope prototype was built in 1931 by the German engineers

4. Electron microscopes have much greater resolving power than light microscopes that use electromagnetic radiation and can obtain much higher magnifications of up to 2 million times, while the best light microscopes are limited to magnifications of 2000 times.

5. Micrograph

6. Electron micrograph

7. Scanning electron micrograph

8. Cell membrane It is selectively permeable. It controls the movement of substances into and out of the cell. Different organelles exist within the cytoplasm.

9. Nucleus Nuclear membrane –double layer with many pores –pores allow exchange of materials between the nucleus and the cytoplasm.

10. Nucleus Chromatin –includes coils of DNA and histones

11. Nucleus Nucleoplasm –contains chromatin, nucleolus, proteins, nucleotides.

12. Nucleus Nucleolus –synthesis of ribosomal RNA.

13. Nucleus The nucleus contains the genetic material DNA, which stores information used to synthesis proteins. The nucleus is surrounded by a double membrane, called the nuclear membrane.

14. Nuclear pores serve as the pathways for the exchange of the materials between the nucleus and the cytoplasm. Nucleoli (singular: nucleolus) are involved in making ribosomes.

15. Mitochondria

16. They are the places where aerobic respiration occurs. Generate adenosine triphosphate (ATP) as a immediate source of energy. Mitochondria have a double membrane. The inner membrane, where most ATP is made, is highly folded. This greatly increases the surface area for ATP production.

17. Chloroplasts

18. Chloroplasts are oval-shaped organelles commonly found in plant cells. Chloroplasts, like mitochondria, have a double membrane. Internal membranes contain the green photosynthetic pigment chlorophyll, which absorbs light energy to make food through the process of photosynthesis.

19. Vacuoles A vacuole is a liquid-filled space within the cytoplasm, surrounded by a membrane called the tonoplast. Plant cells usually have a large central vacuole, which stores water, other useful substances and wastes.

20. Cell Wall It consists of cellulose fibres embedded in a polysaccharide matrix. Plant cells are surrounded by cell walls. Protects plant cells and gives them shape.

21. Vocabularies organism electron microscope cell membrane selectively permeable cytoplasm organelles

22. nucleus synthesis proteins reproduction nuclear membrane nuclear pores chromatin chromosomes nucleoli ribosome rough endoplasmic reticulum

23. mitochondria aerobic respiration adenosine triphosphate (ATP) highly folded increases the surface area chloroplasts pigment chlorophyll photosynthesis

24. vacuoles tonoplast cell sap mineral salts wastes cell walls elastic rigid protects

25. Short questions 1.What is the basic unit of life? 2.How many different types of cells in our body? 3.What is the advantage of electron microscope? 4.List out five organelles which can find in both animal and plant cells.

26. 5.What is the function of cell membrane? 6.Where do the chemical reactions of most cells take place? 7.List out three organelles which can be found in cytoplasm. 8.What is the meaning of selectively permeable?

27. 9.What is the genetic material inside nucleus? 10.How does the nucleus control the activities of cell? 11.What is the function of nucleoli? 12.Where can we find ribosome in cell?

28. 13.Why do scientists call mitochondria as the “ powerhouse ” of the cell? 14.Why is the inner membrane of mitochondria highly folded? 15.What organelle is more abundant in a very active animal cell? 16.What is the shape of chloroplast? 17.How many organelles have double membrane?

29. 18.What are the functions of vacuole? 19.What is the permeability of cell wall? 20.List out the organelles that can only find in plant cells.